Drafting device



Nov. 13, 1934. w. E. SIDNEY ,98

DRAFTING DEVICE Filed April 19, 1930 INVENTOR. 4 1! I /,gyw

' I center line.

parallel lines.

Patented Nov. 13, 1934 UNITED STATES PATENT oF-rrcs This inventionrelates to drafting devices. .One of the primary objects of thisinvention is to provide a drafting device for drawing parallel linessymmetrically disposed at both sides of a Another object is to providesuch a device having means for accurately measuring the distances of thelines from said center-line. A further object is to provide a devicehaving means for drawing radially disposed groups of Still anotherobject of this invention is the provision of a drafting device havingmeans for the securement of the device, for the purpose of drawing aseries of lines variously spaced from and symmetrically disposed to acommon center line. Additional features and advantages of this inventionwill appear from the following description considered in connection withthe accompanying drawing forming a part of this application. In thedrawing:

Fig. 1 is a perspective view, partly in section, of the-preferredembodiment of this invention.

Fig. 2 is a cross-sectional view taken substantially on line 2-2 in Fig.1'.

Fig. 3 is a fragmentary view showing one method of removably mountingthe drafting blades, or rulers, on the device.

Reference being had to the drawing, the drafting device comprises abase-plate 1 of rectangular shape and having its forward side 2preferably bevelled to produce a straight edge for drawing lines. Nearthe forward side, and parallel thereto, is secured by means of screws 3a rectangular, box-like, housing 4, in the narrow sides 5 and 6 of whichare supported the two transverse parallel guide-rods '7 and 8, securedin place, for instance, by means of screws 9.

Upon the guide-rods are slidably mounted the two slide-members 10, 11 toeach of which is secured one of the parallel drafting blades 12, 13.Each slide-member consists of a horizontal bridge portion 14, 15 havingat its ends upwardly directed lugs 16 in which are preferably securelymounted apertured bushings 1'7 slidably engaging the guide-rods 7 and 8.The bridge portions 14, 15 of the slide-members 10, 11 haverectangularly disposed extensions 18 and 19 which, in Figs. 1 and 2, areextended outwardly of the housing sufficiently to produce the paralleldrafting-blades 12 and 13, the edges 20 and 21 of which are alsopreferably bevelled and, if desired, provided with graduations or scalesfor lineal measurements.

t will be noted in the drawing that these extensions 18, 19 glide ontheupper surface of the base-plate and that the blade-portions 12, 13

are bent down level with the lower face of the base-plate l, to lie fiatupon the drafting surface. As shown in Fig. 1 in particular, the majorpart of the bridge-portion 15 is raised above the baseplate to clear theextension 18 of the slide-mem ber 10.

The slide-members 10, 11, respectively and their correspondingdrafting-blades 12, 13 aremove'd simultaneously and equally by turning aknob 22 having a shaft 23 rotatably mounted in a'bushing 24 secured inthe top side of the housing 4.

At the lower end of this shaft is suitably secured 1 a pinion 25 whichmeshes at opposite sides with the parallelly disposed racks '26, 2'7,respectively mounted between, and secured to, the lugs 16 of theircorresponding slide-members 10, 11.

As shown in the drawing, a clockwise'rotation of the knob 22 will causethe drafting-blades lZ,

-13 to separate, and a reversed rotation of said knob will, of course,each other.

For the purpose of measuring the distanceof each blade from acenter-line,a scale-28 having, preferably, two sets of oppositelyreading lineal graduations, is mounted on the'base-plate'upon move saidblades towards spacer-blocks 29" to clear the blade extensions 18 indexline from which readings are made on the scale. When, for instance,radial lines are to be drawn, the blades 12, 13 are moved toward eachother and a pencil-point is inserted between the opposite blade-edges.According to the thickness of saidpencil, the blocks will be ad:- justedso as to bring the index-lines in proper registration with the zero (0);mark on-the scale. The gauge-block-SO is, in the present embodiment,marked to suit measurements taken from the inner edges 20 of thedrafting-blades 12, 13, whereas the block 3l is made use of when drawinglines along the outer edges 21 of said blades.

When many lines are tobe drawn parallel to a given center-lina it may befound advantageous to properly secure the drafting device, upon thedrawing surface. I provide therefor the, two thumb-screws 33 engagingsuitablytapped lugs 34 placed at the back of the housing 4, andpreferably provided with renewableanchoring pins 35 passing through thebase-plateland' which spokes of a gear or wheel, etc.

may be forced into the drawing surface by turning said screws in theproper direction. When the pins are not needed, the screws are turnedup, to bring the'former out of engagement with the drawing surface.

The device may also be used for drawing radially or tangentiallydisposed groups of lines, such as needed, for instance, when designingthe For this purpose, I provide near the front of the device a pivotpin36, preferably of the push-type, which frictionally fits within abracket 37 secured to the housing in any desired manner. is also,preferably, provided with a renewable point 38, as suggested in thedrawing.

The pivot-pin and its point pass through an aperture 39 in the:base-plate; said aperture being preferably made rather large andbevelled to afford a good view of the center-lines drawn on the workingsurface, for the purpose of loeating the center-point.

' At the rear of the housing 4 there is provided in the base-plate aprotractor 40 disposed concentrically with the pivot-pin 36. Thisprotractor is preferably marked with oppositely running graduations, thezero (0) point of which is in line. with the pivot-pin and with thecenterline 44 marked on the front edge 2 of the baseplate.

Instead of permanently securing the draftingblades 12, 13 to theircorresponding slide-members l0, 11 (as shown in Figs. 1 and 2), theformer may be detachably secured to the latter in any desired andsuitable manner, for the purpose of using longer blades, or such oneshaving different graduations, such as. required for making drawings todifferent scales. I In Fig. 8, for instance, the extension 18 of theslide-member 10 is made somewhat longer and is provided with screws 41whereby the blade 12 is removably secured. To insure proper alinement ofthe blade, the latter may be recessed, as at 42, to closely engage theextension'18 Also, when the drafting-blades are made of wood, celluloid,or other relatively soft material, it is advisable to drive the screws41 into metal bushings 43, suitably secured to the blade.

From the foregoing description, the application of the device fordrawing parallellines will be readilyunderstoodandmaybesuccinctlydescribed as follows: Assuming that the drafting-blades be properlyadjusted in relation to the scale 28, the draftsman first brings theblades towards each each other, leaving just enough space therebetweento insert a sharp pencil to draw the original center-line. Then turningthe knob 22 clockwise, he will separate both blades equally from thecenter-line until the proper distance, as read on the scale 28, isobtained and draw the parallel lines, using either the inner or theouter edges of the drafting-blades, according to the gaugeblock fromwhich the'measurements are made.

To draw radially disposed groups of parallel lines, the procedure variesonly in that the draftsman forces the pivot-pin in the center ofrotation and then swings the device around this center to draw theparallel andsuitably spaced lines,

.using the protractor to obtain the desired angular spacing. Thus forinstance, if it be desired to draw a wheel with, say, twelve spokes ofuniform width, the blades are first brought close to- 'the draftsman nowswings the device around 30?,

This pivot-pin as determined with the protractor, and draws the secondset of parallel lines, at the same time also marking on the drawingsurface a point corresponding to the zero line of theprotractor. Readingfrom this point, he again swings the protractor around 30 to draw thethird set of parallel lines, and so forth until the twelve spokes havebeen outlined.

It will benoted that by this procedure it is not necessary (as is thecommon drafting-room practice) to first draw the center line of eachindividual spoke and then space off the arms; but on the contrary, thelatter may be drawn directly,

thus greatly expediting the work and improving the accuracy thereof.

If however, it is desired to draw the centerlines of. all the spokes,the blades are brought together, after each angular shift, to establishI saidcenter-lines and then separated to draw the spokes proper.

In addition to the above described practical applications of thisdevice, several others will suggest themselves to a draftsman afterbecoming more familiar with it.

As will be understood, as suggested herein, there may be many changesmade in the construction and arrangement of the details of my inventionwithout departing from. the field and scope of the same, and I intend toinclude all such variations, as fall within the sphere of the appendedclaims, in this. application inwhich the preferred form only of myinvention has been disclosed.

I claim:

1. In a device of the character described, a baseplate including aprotractor and a pivot-pin centrally of said protractor; a pair ofparallel drafting-blades upon the base and movable toward and away fromeach other, and means to move said blades simultaneously toward and awayfrom each other whereby lines radially disposed to said pivot-pin andlines parallel and symmetrically disposed to said radial lines may bedrawn without shifting said base-plate.

2. In a device of the character described, a base-plate including aprotractor and a pivot-pin centrally of said protractor; a pair ofparallel guide-means mounted on said base for movement toward and awayfrom each other whereby lines radially disposed to the pivot-pin andlines fie parallel and symmetrically disposed to said radial plate formovement toward and away from each other whereby lines radially disposedto said pivot-pin and lines parallel and symmetrically disposed to saidradial lines may be drawn without shifting said base-plate, and meanspositioned on the base-plate to measure the angle of rotation thereofabout the pivot-pin.

,4. In a drafting device of the character described, a base plate; ahousing mounted thereon; a pair of parallel guide-rods mounted in saidhousing; a slide-member slidably mounted on each guide rod; an extensionsecured at right angles to each slide-member, said extensions beingdisposed in parallel edge to edge relation; means positioned on saidextensions for the removable sec'urement thereto of drawing blades andthe like; rotatable means mounted in said housing to simultaneously movesaid slide-members in opposite directions; a pivot-pin mounted forvertical movement on the housing and adapted to engage the drawingsurface upon which the device is used, and means positioned on saidbase-plate to measure the angle of rotation thereof about saidpivot-pin.

5. In a drafting device of the character described; a base plate; ahousing mounted thereon; on; a pair of parallel guide rods mounted insaid housing; a slide-member slidably mounted on each guide rod; anextension secured at right angles to each slide-member, said extensionsbeing disposed in parallel edge to edge relation; means positioned onsaid extensions for the removable securement thereto of drawing bladesand the like; rotatable means mounted on said housing to simultaneouslymove said slide-members in opposite directions; a pivot pin mounted forvertical movement on the housing and adapted to engage the drawingsurface upon which the device is used, said base-plate having an arcuateaperture concentric with said pivot pin and provided with graduations tomeasure the angle of rotation of the base plate about the pivot pin.

6. In a drafting device of the character described; a base plate, ahousing mounted thereon; a pair of parallel guide rods mounted in saidhousing; a slide-member slidably mounted on each guide rod, eachslide-member comprising a horizontal bridge portion and upwardlydirected apertured lugs adapted to slidably engage said guide rod; arack-member positioned on each slide-member in parallel relation to itsguide rod; a gear rotatably mounted on said housing in meshingengagement with the rack-members; means to rotate said gear; anextension secured at right angles to each slide-member; said extensionsbeing disposed in parallel edge to edge relation, means positioned onsaid extensions for the removable securement thereto of drawing bladesand the like, and means mounted on the base plate to measure thedistance between said extensions.

'7. In a drafting device of the character described; a base plate; ahousing mounted thereon; a front guide rod and a rear guide rod mountedin parallel relation in said housing; a slide-member slidably mounted oneach guide rod, each slide-member comprising a horizontal bridge portionand upwardly directed apertured end-lugs adapted to slidably engage theguide rod; an extension secured at right angles to each slidemember,said extensions being disposed in parallel edge to edge relation; thebridge portion of the front slide-member being raised to clear theextension of the rear slide-member; a rack-member positioned on eachslide-member in parallel relation to its guide rod; a gear rotatablymounted on said housing in meshing engagement with both rack-members,and means to rotate said gear whereby said slide-members will movesimultaneously in opposite directions.

WILLIAM E. SIDNEY.

